Abstract
Ultraviolet and visible (UV–Visible) spectroscopy in conjunction with
chemometrics modelling, was successfully applied to objectively
differentiate grape juice press fractions (Vitis vinifera,
cultivar Pinot Noir) for sparkling wine production. Two measurements
modes were applied: (i) reflectance using a fiber optic probe in-line
and (ii) transmission using a benchtop spectrophotometer. Different
wavelength ranges for UV–Visible spectroscopy were evaluated and their
ability to measure total phenolic concentrations in grape juice press
fractions was compared. The differentiation of free run, early and late
press fractions shows promise as a tool for the rapid discrimination of
juice fractions when grapes for sparkling wine are pressed. Calibrations
for total phenolics were prepared from press fraction spectral data
using partial least squares (PLS) regression with a large number of
wavelengths (230–700 nm) and multiple linear regression (MLR) using a
small number of key wavelengths (230, 240, 280, 290, 520 nm).
Calibration performance for both reflectance and transmission spectra
was similar, but the best performing calibration used reflectance
spectra at 240 and 290 nm (R2val = 0.95;
SECV = 0.023 g/L; CV = 4.2%). Reflectance spectroscopy can thus be used
in-line to predict total phenolics in grape juice with an acceptable
accuracy and to discriminate press fractions. Insights arising from this
research suggest a future possibility of objective, real-time
discrimination of grape juice for better process control, monitoring and
optimization of winemaking practices.
Original language | English |
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Article number | 106810 |
Number of pages | 9 |
Journal | Food Control |
Volume | 123 |
Early online date | 01 Feb 2021 |
DOIs | |
Publication status | Published - May 2021 |